This wholesale change breaks down llvisualize into multiple modules

This wholesale change breaks down llvisualize into multiple modules
to allow easy extensibility and to reduce memory footprint when
running with large logs.

llascii.pm is the module used for timing analysis, html and graph generation
(--vfssummary option). No new features have been added, but lot of
redundant code has been removed.

llgtk.pm is the visual component for the gtktree. This has been completely
rewritten, in part due to bugs #1271 and #717. The --serverrpc switch has
(for stitching server logs into client view) been fixed. The --uml option
will allow loading of logs which are time warped at multiple places in the log.

llcommon.pm contains code that is common to both the analysis mode (--vfssummary option)
and the visual mode.

llconsts.pm contains the constants, and any global variables used.