Docs for ycmd configuration.

Fixes #26.
Minor README clarification & formatting.
Minor refactoring
run_tests.sh can now be told to skip build step
More refactoring
RemoveIdentifierFreeText() now implemented in Python

And tested.
ExtractIdentifiersFromText implemented in Python

Plus tests.
Identifier collection now in Python, not C++

Should make it easier to support different identifier definitions for
various languages.
Deleting obsolete test
Regexes for CSS and HTML identifiers.
Minor style fixes
Further tweak to HTML identifier regex
Per-language custom identifier collection works.

Also tests for this.
Minor refactoring
Extra test for IdentifierCompleter (C++)
Refactoring RequestWrap to use explicit cache
Added IsIdentifier method to identifier_utils
Making IsIdentifier handle None as text
Implemented StartOfLongestIdentifierEndingAtIndex()
StartOfLongestIdentifierEndingAtIndex now faster

Used to be O(n), now it's O(log(n))