Provide parameter values for each distribution separately +
honor semantics of common parameters like probability in [0,1] etc.

Few minor fixes of bugs discovered along the way.

Plus 'pgamma' external implemented.

Merge pull request #559 in G/fastr from ~MILOSLAV.METELKA_ORACLE.COM/fastr:utf8ToInt_builtin to master

* commit '0e33da46':
  Improved casts and removed extra specialization in utf8ToInt() builtin..
  Additional eclipse formatting.
  Implemented utf8ToInt builtin.

* commit '770b252b':
  use Java XZ; implement xzfile, bzfile .Internals

Merge pull request #570 in G/fastr from ~STEPAN.SINDELAR_ORACLE.COM/fastr:feature/more-stats8 to master

* commit 'e1295d32':
  Stat externals: qbeta, qf, qchisq
  Stat externals: ppois, qpois

Merge pull request #571 in G/fastr from ~LUKAS.STADLER_ORACLE.COM/fastr:bugfix/attr_in_specials to master

* commit '08375d00':
  use attribute node in SpecialsUtils

Merge pull request #550 in G/fastr from ~LUKAS.STADLER_ORACLE.COM/fastr:feature/cache_calltarget to master

* commit '79a3e14b':
  cache CallTargets in PolyglotEngineRootNode

Merge pull request #530 in G/fastr from ~LUKAS.STADLER_ORACLE.COM/fastr:feature/local_condition_handling to master

* commit '3ff79c88':
  store handler and restart stacks in frame slots only on demand

+ necessary DPQ/RMath methods
+ move all XChisq to Chisq.java

Merge pull request #569 in G/fastr from ~LUKAS.STADLER_ORACLE.COM/fastr:bugfix/cast_list_node to master

* commit 'af437d36':
  fix ordering of transferToInterpreter and node insertion in CastListNode

Merge pull request #566 in G/fastr from ~STEPAN.SINDELAR_ORACLE.COM/fastr:feature/more-stats7 to master

* commit 'b07b1106':
  Stat externals: qt, pt, punif, dunif, qunif, pgeom

Merge pull request #567 in G/fastr from ~LUKAS.STADLER_ORACLE.COM/fastr:bugfix/visibility_boolean to master

* commit '2cda4baf':
  set visibility in FunctionExpressionNode
  check for boolean frame slots in “executeEndOfFunction” and produce proper error message

Merge pull request #565 in G/fastr from ~LUKAS.STADLER_ORACLE.COM/fastr:bugfix/convert_index_NaN to master

* commit '3aadff8d':
  prevent NaN to 0L conversion in subset/subscript specials

* commit '461c62c8':
  A couple of tests added
  .fastr.interop.evalFile builtin added

Merge pull request #563 in G/fastr from ~LUKAS.STADLER_ORACLE.COM/fastr:feature/remove_package_override to master

* commit 'abbb9dc6':
  remove overrides that are not necessary any more

* commit '2283c3f2':
  more concise FastRSyntaxTree
  more resilient Utils.dumpFrame

Merge pull request #561 in G/fastr from ~LUKAS.STADLER_ORACLE.COM/fastr:feature/rename_source_section to master

* commit '03f7f432':
  rename sourceSectionR to sourceSection where appropriate

Merge pull request #557 in G/fastr from ~LUKAS.STADLER_ORACLE.COM/fastr:feature/force_sources to master

* commit '806c6a62':
  new FastROptions.ForceSources to generate source sections for all nodes

* commit '82a2dc76':
  lhs might be also a RCallBaseNodeWrapper

Merge pull request #555 in G/fastr from ~STEPAN.SINDELAR_ORACLE.COM/fastr:feature/more-stats6 to master

* commit '97f9da26':
  More tests for stats functions
  Fixes in nmath ported code.
  Externals for logis distribution: dlogis, qlogis, plogis

Merge pull request #556 in G/fastr from ~LUKAS.STADLER_ORACLE.COM/fastr:feature/thread_safety to master

* commit '185b8b62':
  thread safety for UseMethodFunctionLookup, remove UseMethodInternalNode and NoGenericMethodException
  minor cleanups
  thread safety in RCallNode and TemporarySlotNode
  thread safety in PrepareArguments (use DSL)
  thread safety in ReadVariableNode
  thread safety in CallArgumentsNode
  thread safe and simpler PostProcessArgumentsNode and ArgumentStatePush
  thread safety in CallMatcherNode
  thread safety in PromiseNode
  thread safety in Lapply, BinaryBooleanScalarNode and FunctionDefintionNode

Merge pull request #560 in G/fastr from ~LUKAS.STADLER_ORACLE.COM/fastr:feature/paren_special to master

* commit '484517a4':
  turn parens into builtin + special