Fix the build for MRI 1.9.2 and 1.9.3

RSpec 2.0 is buggy
Fix wrong indentation from b9d689f
Open source files in binary mode

Opening non-UTF-8 files as UTF-8 succeeds in some cases and will throw
<ArgumentError: invalid byte sequence in UTF-8> when comparing against a
regexp. Forcing Ruby to use binary mode will keep strings as ASCII-8BIT
and seems to work on all current versions of Ruby.

Moreover, there is no way to know for sure which encoding is used
without heuristics or parsing the potential encoding shebang thus binary
mode is probably safer.
Remove unsafe scenario

This would overwrite user's ~/.simplecov if present and testing this
behaviour is not particularly relevant.
Make sure filepaths are expanded on JRuby

Fixes the build on JRuby
Merge pull request #201 from infertux/fix_build

Fix the build