upgrade to herwigpp 2.7.1 and thepeg 1.9.2
autotools: bump gettext to 0.19.2 and fix Darwin compilation

Gettext does not compile on Darwin platform. The following updates
gettext to 0.19.2 (latest) version and fixes Darwin compilation
errors.

Signed-off-by: David Abdurachmanov <davidlt@cern.ch>
Merge pull request #906 from davidlt/fix-darwin-gettext

autotools: bump gettext to 0.19.2 and fix Darwin compilation
Merge pull request #888 from mkirsano/toherwigpp271_1

upgrade to herwigpp 2.7.1 and thepeg 1.9.2
Merge remote branch 'origin/IB/CMSSW_7_1_X/stable' into IB/CMSSW_7_0_X/stable
Merge remote branch 'origin/IB/CMSSW_7_2_X/stable' into IB/CMSSW_7_0_X/stable