Template tag documentation

Expand the boostrap_pagination documentation to display the other options
Remove kwargs and args mentions.
Captialise Usage and Example
Expand the documentation on bootstrap_form and bootstrap_form_errors
Expand the doucmentation on the bootstrap_formset and bootstrap_formset_errors tags
Add info on what parameters can be set when using the buttons tag
Add bootstrap_alert to the templatetags page
Update structure of documentation
Add a link to the Bootstrap documentation for all icons
Add documentation describing the arguments that the bootstrap_button accepts
Add documentation describing the arguments that the bootstrap_label accepts
Add documentation describing the kwargs that the bootstrap_field tag accepts

Author: SamTShaw