- Parse "-isystem" include path entries and pass them to flycheck

Signed-off-by: Vicent Seguí Pascual <vseguip@picvisa.com>
Correct capitalization of AND in comment

Signed-off-by: Vicent Seguí Pascual <vseguip@picvisa.com>
Merge pull request #6 from vseguip/feature/isystem

Parse "-isystem" include path entries and pass them to flycheck