Changes for version 1.03
- many cleanup: Tcl::call now much smaller and does not tracks widgets anymore; $Tcl::STACK_TRACE, %widget_refs, sub wcall, etc
- proper disposal of CODE REFs when they are no more needed on tcl side.
- new test t/disposal-subs.t
- Tcl::call processes 'after' differently
- use direct object syntax for calls to 'new'
- fixed minor typos in POD
- removed superfluous Solaris check in Makefile.PL
- add Travis-CI configuration
- Tcl - Tcl extension module for Perl