Trimmed white space.
Added Stata extensions.
Added .ado and .sthlp samples for Stata.

The author of this message, mwhite-IPA, is the source of these samples.
Added .mata sample for Stata.

Source: http://www.stata.com/help.cgi?m1_first
Added .do sample for Stata.

Source: http://www.stata.com/help.cgi?regress
Added .ihlp sample for Stata.

The author of this message, mwhite-IPA, is the source of this sample.
Added .doh and .matah samples for Stata.

Source: http://www.stata.com/help.cgi?include
Added Text only lexer for Stata.
Merge branch 'pr/1002' into mergepullrequests