Updated installation instructions

Split the installation instructions into different sections. Added a section to
explain how to do installation just for the project using Bundler.

Also added instructions how to run jekyll if Bundler has been used to install
the gems.
Track Gemfile.lock.
Updated location
Homepage link durch pad ersetzt
Merge branch 'gh-pages' of github.com:ironjan/codefor.de into gh-pages
meetings aktualisiert
Update events.yml
Aktualisierung der Code for München Projektseiten
Update index.html
Merge pull request #196 from felixkqb/patch-1

Update index.html
Add felixkqb
Merge pull request #192 from ironjan/paderborn

Updated location
Merge pull request #194 from saerdnaer/patch-1

Update events.yml
new date oklab cologne
Merge pull request #198 from marcel12bell/gh-pages

new date oklab cologne
Merge pull request #197 from stkdiretto/gh-pages

added event: occ14
update events
update events

Conflicts:
	_data/events.yml
new blogpost jugend hackt
add new photo for jugendhackt