Minor reduction of code duplication
Minor code reduction
Removed some code duplication.
Added '--enable-lto' option.

While nothing in tilda is in any way performance critical, link
time optimization may produce smaller binaries (in my case, the
savings are a bit more than 4K for either -O2 or -Os) and comes
basically for free (tested with gcc 4.8.2).

This option is not enabled by default, since it needs testing
and older compilers (GCC < 4.6) don't support link time
optimizations out of the box.

In the future, one may consider enabling the option by default
if a recent compiler and toolchain is found.
Use spaces for indentation.
Don't propagate event when switching tabs.

This means keys bound for tab switching will consistently never be passed to the
shell.
Don't set tilda active when sub-windows are open.

The wizard uses "disable_auto_hide" to say that its window is open.  If the
window is set active on mouseover when the settings window is open then the
settings window will be underneath the terminal and not be usable at all.

This reverts "1bd3bbffdac68cc48028c0eef6cbd1a034e0ece0"
Tilda will not attempt to set itself active on mouseover.
Allow context menu activation with menu key
Switch tab with mouse (back and forward) buttons

 * Fixes #58
Merge pull request #56 from bnkr/focus-stealing

Tilda will not attempt to set itself active on mouseover.
Merge pull request #54 from bnkr/always-capture-tab-changes

Always capture tab changes and don't pass key to terminal.
Merge pull request #45 from Ed-von-Schleck/cleanup_03

Minor cleanups
Minor reduction of code duplication
Minor code reduction
Removed some code duplication.
Allocate the struct 'tilda_window' on the stack of 'main()'.

Apart from the (minor) benefit of avoiding a heap allocation,
this removes a bit of the necessary error handling.
Merge branch 'Ed-von-Schleck-allocate_tilda_window_on_stack'

 * Fixes #46
Merge pull request #52 from Ed-von-Schleck/lto

Added '--enable-lto' option.
Remove unused variable