Adapted DashDoc to Dash's (v1.9.3) new URL scheme (keys, query)

- also modified and extended the syntax_docset_map: one ST syntax spec maps to a sequence of Dash docset keys, in general (see http://kapeli.com/dash_plugins)
Make DashDoc's settings overridable through project-specific (.sublime-project) files

- Modifications/additions to syntax_docset_map in .sublime-project files are *merged* with the default docset mapping.

Thus, users only need to provide the specific syntax-to-docset mappings of interest in their .sublime-project files — all other default mappings remain intact.

- Syntax sensitivity is the default now.
Syntax sensitivity is the default now
Make DashDoc work with Python 3 (and thus Sublime Text 3)
Make DashDoc recognize a SublimeHaskell buffer as a Haskell buffer
Adapted the README
Adapted the README
Merge branch 'master' of github.com:Teggy/DashDoc

Conflicts:
	README.md
Merge pull request #23 from Teggy/Dash-v1.9.3

Added support for new calling convention in Dash v1.9.3