Add a minimal .gitignore.

Ignore PYC files, as well as build artifacts.
Fix Python 3 compatibility.

* iteritems() is Python 2 only
* In Python 3, the except handler's "name" is a string, not a node
Fix importer fixup() of module and from-symbol name.

This makes the import_test pass again.
The index_test have to be adapted to check for the right result.
Fix swallowing up trailing comments in an import block.

Fixes the remaining failing test test_imports_dont_delete_trailing_comments.
Add score and location to the repr() of SymbolIndex.
Fix dictionary order dependence in creating aliases.

This leads to sporadic failures under Python 3 with randomized hash.
Add a .coveragerc file and ignore coverage output.
Ignore htmlcov/ coverage report output.
Allow specifying different a module blacklist regex.
Do index stuff in __init__.py files.
Add test for indexing files with build_index(), increase coverage.
Merge pull request #2 from birkenfeld/local

A collection of fixes to make the test suite pass again, plus more test coverage.