Merge pull request #1 from qgis/master

Forked source update request
Update foreword.rst
Update modeler_hydro_calculator.rst
Update answers.rst
added example using QGIS startup parameter --code to introduction
Merge pull request #254 from diethard2/master

added example using QGIS startup parameter --code to introduction
Fix dead link and typo from #234
Merge pull request #257 from yjacolin/deadLinks

Fix dead link and typo from #234
Merge pull request #244 from Qgis-Tr-kr/master

Fix broken image links in Training Manual
Explain live update of the color button for print composer.