Improved VIM configuration

CHANGELOG:
	- Merged lines in groups
	- Added more explanatory comments
	- Added NERDTree shorcut & customizations
	- Added "Surround" plugin
	- Applied UTF8 encoding
	- Adjusted VSP and SP (split screen) commands

Adjusted change directory command behavior

Upgraded installation shell script

CHANGELOG:
	- don't copy dotfiles for stuff that is not in use by currently logged in user
	- don't activate OH-MY-ZSH configuration file if OH-MY-ZSH is not installed
	- fixed OH-MY-ZSH copying operation
	- remove BACKUP dir if it exists before backing up

Removed unnecessary plugin

Separated OH-MY-ZSH and ZSH dotfiles

Added installation shell script