Introduced changes on vimrc

Functions
=========
  - Removed  => Warn about Extra Whitespace
  - Removed  => Warn about Tab while ExpandTab
  - Modified => Highlight Extra Whitespace (Search instead of ErrorMsg)
  - Modified => Highlight_Extra_Tab (Search instead of ErrorMsg)
  - Added    => Toggle_Line_Number_Mode to handle line numbers

Visual
======
  - Removed => Status line format (Deprecated with tmuxline)

Leader Mappings
===============
  - Modified => Toggle Highlight Extra Characters to look at “Highlight_Extra*” Functions
  - Added    => Toggle_Line_Number_Mode() global mapping

* Introduced new section to load functions when loading vim