Implemented support for perl-style regular expression in (g)regexpr.

com.oracle.truffle.r.native/fficall/src/jni/pcre_rffi.c

...om/oracle/truffle/r/nodes/builtin/base/GrepFunctions.java

...fi/src/com/oracle/truffle/r/runtime/ffi/jni/JNI_PCRE.java

...le.r.runtime/src/com/oracle/truffle/r/runtime/RError.java

...untime/src/com/oracle/truffle/r/runtime/ffi/PCRERFFI.java

...est/src/com/oracle/truffle/r/test/ExpectedTestOutput.test

.../oracle/truffle/r/test/builtins/TestBuiltin_gregexpr.java

...m/oracle/truffle/r/test/builtins/TestBuiltin_regexpr.java

mx.fastr/copyrights/overrides