Changed tabs such that all are always visible

Tabs are now uniform in size and shrink if necessary instead of being hidden.
Removed all code related to invisible tabs

All tabs should always be visible now, so there was no more need.
Cleaned up some compiler warnings

Removed cases of unused variables, unused functions, implicit declarations,
and a deprecated function (XKeycodeToKeysym).
Updated the README file
Increased the length of tab titles

Tabs are large enough to merit longer titles, and clipping of the titles is now
handled by X instead of manually trimming the string anyway.
Also some general code cleanup and removing the title parameter from
rxvt_tab_width (no longer used).
Set a sensible default for transparency tinting

Set the pseudotransparenty to 25% when not set. Also changed a few configuration
defaults in lxvtrc
Merge branch 'master' into dev

Merge changes for release 0.5.5
Fixed a rendering and compile issue

Fixed a compile issue when --disable-xft was specified
Fixed a rendering issue when --disable-256colors was specified
Merged --disable-tabbar and --disable-tabs

These two options seemed redundant, especially since the tabbar can be disabled
with a configuration option.
Also fixed some compile issues when --disable-tabs was specified during
configure.
Fixed an issue with the last commit

Fixed a problem with the tab bar not rendering properly.
Changes to the tab bar interface

Created new icons for the 'new' and 'close' terminal buttons.
Removed the 'left/right' buttons, as I don't see a reason for them now that
all tabs are always visible.
Removed all references to left/right icons
Made tabs resemble Firefox/Chrome style

Tabs now have tapered sides and overlap, more like firefox/chrome.
Suble changes to the new tab button pixmap.
Fixed a redraw bug when a tab was moved to the last position.
Fixed a minor graphical bug in tabs
Reverted some tab drawing changes from 47f2d4a409

Adjusting some of the angle calculations cause some rendering issues with tabs.
Reverting these for now - save these changes for later.
Fixed an issue with tab highlight rendering

Fixed tab highlights to correct for the extra space caused by tapered tabs.
Added a package script for Arch Linux.
More work on the tab UI

Converted the new tab button to a more Firefox style button.
Some cleanup on the XColor allocation code
Cleaned up the indentation mess in tabbar.c
Fix for automake 1.13