app: Fix doc

Sources for statusbar areas cannot be a treeview name.
treeview: status: Fix text possibly truncated on start

On start/location change, there was a check_status() called on
change_location(), i.e. before the list had been updated/filled. This
would lead to the string used for width calculation having no files/size
and could result in a too small width.

We now call check_status() after the list has been been filled.
list: Fix emitting notify::location before list is filled
treeview: Minor fix

Tree might not remove non-existing children anymore from a node-children
because the test was a bit too restrictive, and needed the get_children()
to be have been for the same node types, instead of including them.
tree: When sync-ing with list and in EXPAND_MAXI, refresh children

Such an update would be done when the change of location came from the
tree, but not from the list (since then when node-chidren happens the
tree hasn't yet changed location).
tree: Fix maxi expand not removing deleted nodes

expand_row() was expected to be called from UNKNOWN or NEVER, not e.g.
PARTIAL, and therefore it wouldn't remove any node on tree that doesn't
exist anymore when getting children from another maxi expanded row on
tree or sync_with.

We now go always through set_chidren() to handle it properly.
Bump to 0.1.1; Update HISTORY