Add the following additional routines from the R tre modifications:

tre_regnexecb
tre_regexecb
tre_regncompb
tre_regaexecb
tre_regcompb

These work on raw byte vectors.
Add the following additional routines from the R tre modifications:

tre_regnexecb
tre_regexecb
tre_regncompb
tre_regaexecb
tre_regcompb

These work on raw byte vectors.

Add REG_USEBYTES define used by the above.
Make use of REG_USEBYTES.
Merge pull request #14 from opoplawski/R

R additions