vcs: use a real two part name for merge operation. - expose settings into vcs_settings for easier override later

diffs: added handy quick file selector in diffs views.

pyramid: fixed some deprecated calls.

tests: fixed some pytest deprecated calls, and warnings.

dependencies: bumped rhodecode-tools to 1.0.0 release

dependencies: bumped few libraries. - atomicwrites==1.2.1 - attrs==18.2.0 - dogpile.cache==0.6.7 - psutil==5.4.7 - pathlib2==2.3.2 - subprocess32==3.5.2 - gevent==1.3.6 - greenlet==0.4.15 - pytest==3.8.1 - py==1.6.0 - pytest-cov==2.6.0 - pytest-timeout==1.3.2 - coverage==4.5.1 - psycopg2==2.7.5

tests: use safer test id generator. - this should handle pure boolean ids

hooks: pass in store_path into env for hooks.

scm_app: add more debug info when unhandled errors happen on vcsserver.

diffs: limit commit line context to MAX_DIFF to prevent packetOverflow errors.