DarcsPatchLexer: Update for Darcs 2
DarcsPatchLexer: Update for Darcs 2

Update DarcsPatchLexer, primarily due to differences in the output in darcs 2.
Specifically:

  * Relax patch requirements: operators { and } are no longer special and
    ±/hunk/etc... are no recognized with or without them.

  * Tighten keyword recognition, now uses list of hunk, addfile, etc...

  * Keywords now have optional spacing before hand, due to the (common) case
    in darcs 2 of: ] hunk ...

  * Hunk insertions/deletions now recognize the [_*_] special characters

--HG--
branch : trunk

nsfmc/pygments,Khan/pygments,Khan/pygments,dbrgn/pygments-mirror,dbrgn/pygments-mirror,nsfmc/pygments,kirbyfan64/pygments-unofficial,kirbyfan64/pygments-unofficial,Khan/pygments,kirbyfan64/pygments-unofficial,Khan/pygments,Khan/pygments,kirbyfan64/pygments-unofficial,dbrgn/pygments-mirror,kirbyfan64/pygments-unofficial,Khan/pygments,nsfmc/pygments,dbrgn/pygments-mirror,nsfmc/pygments,Khan/pygments,kirbyfan64/pygments-unofficial,kirbyfan64/pygments-unofficial,kirbyfan64/pygments-unofficial,Khan/pygments,nsfmc/pygments,dbrgn/pygments-mirror,Khan/pygments,nsfmc/pygments,dbrgn/pygments-mirror,nsfmc/pygments,nsfmc/pygments,kirbyfan64/pygments-unofficial,dbrgn/pygments-mirror,dbrgn/pygments-mirror,nsfmc/pygments,nsfmc/pygments,kirbyfan64/pygments-unofficial,dbrgn/pygments-mirror,dbrgn/pygments-mirror,dbrgn/pygments-mirror,dbrgn/pygments-mirror,Khan/pygments,dbrgn/pygments-mirror,nsfmc/pygments,kirbyfan64/pygments-unofficial,Khan/pygments,kirbyfan64/pygments-unofficial,nsfmc/pygments,Khan/pygments,kirbyfan64/pygments-unofficial,kirbyfan64/pygments-unofficial,Khan/pygments,nsfmc/pygments,nsfmc/pygments,Khan/pygments,kirbyfan64/pygments-unofficial,kirbyfan64/pygments-unofficial,Khan/pygments,dbrgn/pygments-mirror,nsfmc/pygments,Khan/pygments,nsfmc/pygments,dbrgn/pygments-mirror,dbrgn/pygments-mirror