Code indentation
Add cfw:event struct for common formatting.

The cfw:event struct:
 - title:        event title [string]
 - start-date:   start date of the event [cfw:date]
 - start-time:   start time of the event (optional)
 - end-date:     end date of the event [cfw:date] (optional)
 - end-time:     end of the event (optional)
 - description:  event description [string] (optional)
 - location:     location [strting] (optional)
 - source:       [internal] source of the event

When used by the calfw plugins (cal,ical, etc) they can be displayed in a common way. cfw:event has several formatting functions used by the calendar.
 - cfw:event-overview:        To get an overview of the event (month, 2-week & week view)
 - cfw:event-days-overview:   Overview in day-view.
 - cfw:event-period-overview: Overview of periods (same for all views)
 - cfw:event-detail           Detailed information of the event for the detail-view

The formatting can be customized by the user with several formatting strings:
 - cfw:event-format-overview
 - cfw:event-format-days-overview
 - cfw:event-format-period-overview
 - cfw:event-format-detail
 - cfw:event-format-title
 - cfw:event-format-start-date
 - cfw:event-format-start-time
 - cfw:event-format-end-date
 - cfw:event-format-end-time
 - cfw:event-format-location
 - cfw:event-format-description

* Adapted ical and cal plug-ins to use cfw:events
* Add some convenience functions for date/time

* Bug fix regarding period stacking:
 Holes between different periods were not considered by the stacking algorithm:

    a a a a
    b b c d d
      c

 But expected was

    a a a a
    b b   d d
      c c
Improved: whitespace stripping
patch agenda buffer related bug and etc

patch "Selecting deleted buffer" bug
remove tags from title
remove time related string from title
remove org file name from title
set title color as default color(except deadline item)
Merge pull request #29 from skyer9/patch-1

patch agenda buffer related bug and etc
Merge branch 'cfw-event' of https://github.com/ahilsend/emacs-calfw
works with org-link
Merge pull request #31 from skyer9/patch-3

works with org-link