Add basic support for Objective-C

Snippet completion was broken since with Objective-C it appears that
having more than one typed-text chunk is possible. Also allow
Objective-C in irony-known-modes.

Thanks Arthur Evstifeev (ap4y on Github) for reporting the issue!
Handle multiple responses(#92)
Merge pull request #93 from kumar8600/handling-multiple-responses

Fix irony-handle-output to accept multiple responses (#92)
Adjust regex in irony-split-command-line.

The regex in the irony-split-command-line did not match the escaped
strings it was supposed to, resulting in many failures in a well-tested
legacy build environment.  Even when using the example string in the doc
string, the existing regex did not correctly match the quoted strings.

The new regex matches both the aforementioned legacy build environment
as well as the doc string example.