Added symlinks to built powerline-daemon executables.

- added the symlink in scripts so that as soon as the powerline client is built
  the binary is available in path.
Altered vim tab handling.

- set standard hard 8 column tabs in vimrc, ftplugin scripts should not alter
  this.

- new function created to alter buffer to use tabs instead of spaces ( using
  shell commands expand and unexpand.) after reading the file and restoring
  afterwards. Requires a tab length parameter to be passed to the (un)expand
  command.

- added auto commands to alter ruby and python files to use the new function.