Registry refactor.

Simplify registry data structure.
Simplify registru functions.
Optimisations.
Merge branch 'master' into registry_refactor
Cleanup.

Enforce sane loading order.
Group global initialization.
Minor logging fixes.
New option: g:syntastic_bash_hack.
Formatting.

Improved folding.
Consistent naming of private methods.
Moving a few functions arround.
Bug fix: checker ordering.  Formatting.
Refactor of quiet_message filters.

Optimisation: merge handling of global and per-checker filters.
Feature: allow [] and '' values for quiet_messages filter elements.
Feature: allow overrides for quiet_messages filters.
Feature: buffer-local auto_jump and quiet_messages.
Safety: add magic specifiers to catch regexps.
Cleanup: minor restructuring for the forthcoming foreign checkers
feature.
Add buffer-local versions for auto_loc_list and loc_list_height.
More preparations for the foreign checkers feature.
jscs: add exit code 2 as valid (new in JSCS 1.3.0).
Merge branch 'registry_refactor'
Move preprocess functions to their own file.
Small fix.
pyflakes: update errorformat.
Security: disable the perl checker by default.
README: minor updates, rewording, and formatting.
README: put examples in accord with the defaults.
Allow foreign checkers to call foreign preprocess and postprocess functions.
Simplify main/1 heads
Properly add deps/*/include to header file path
Don't forget about ebin/