wrap_args() must chack that arg contains '='

Otherwise for

Pandoc! html -Fvimhl -FparaToSpanBlock -S --standalone

i am getting wrong command instance

pandoc -t html -o "example.html" -Fvimhl" -FparaToSpanBlock" -S
--standalone "example.md"

that won't produce new document
fixed technical error in previous commit
fix: using re.search() instead re.match()
Merge pull request #49 from lyokha/master

wrap_args() must check that arg contains '='