gitconfig changes

* `git trim` now also trims merged branches
* renamed `git cleanup` to `git clear` as a way of resetting the branch and clearing all changes made to it
Now also updating system gems
`git go` can only create new branches
Fixed default terminal theme
Minor prompt changes
Improved startup performance
Added `git squash` alias
Added php and some other packages to brew installs
Removed unused ssh config
Minor prompt tweaks
Fixed homebrew installer
Updated installed php version
replaced references to 'pkruithof' with 'cleentfaar'