bugfix application deadlock at startup because of global vars dependency

TaskTreeModel need Globals. So we make sure that
 Globals is create before TaskTreeModel
 TaskTreeModel is created separately from Globals
 TaskTreeModel is then passed to Globals

TaskSelectionModel follow the same scheme for consistency purpose
TaskTreeView::setColumnsSizes()
passing parent to base class
notify column change before and after
treemodel gets correctly updated when column change is requested
having column 0 and 1 static is now only managed in Globals

may be not the best place, however it is better than sparse this
column mgmt all around in the program
cosmetics
Globals::setColumnSize
tasktree gets his columns resized at startup
keeping track of manual resize of column
cosmetics
add commented code for testing column change