cp#1000072: Load external documents when refreshing caches.

Rather than just clearing the existing caches and loading the external
documents on demand as the formula cells gets re-calculated.  This has two
advantages: 1) when the loading itself fails, we can keep the existing cache
rather than turning all affected cells to error cells, and 2) this prevents
on-demand loading after the external linkes get refreshed, which can make
scrolling very slow & painful.

Change-Id: Ie8243f6f94c5e477964413ab83f6b4b746fe3220
cp#1000072: Stop the external doc shell timer while mass-updating.

To prevent collision with the timer wanting to purge the doc cache
while updating external links.

Also, show progress bar, and make the timer interval and the document
cache life span longer.

Change-Id: I325984c8fa68425a2621cf8f9c016463291afc89
cp#1000072: Purge one document shell at a time, to avoid freeze.

Import especially when we have a whole bunch of large-ish documents open
in the background.

Change-Id: I614e6daab3481c09dae47c8407497d77aec40480
Localize this string.

Change-Id: I88b205d36eede5e63af46f8581896d980b6aa27d
cp#1000072: Populate cache tables when updating all external links.

This way, even after the loaded doc shells get purged due to timeout,
we won't reload those external documents from disk again.  One caveat
is that we currently don't pre-populate empty cells even if they are
referenced by the host document.

Change-Id: I1de2987836bf2fc5d9d7044b406fb99faa534164
Turn the mouse cursor to the "wait hand" during the external link update.

Change-Id: I983127828b28c72dd12d4778b88051964e9bceaa
Let's not use ScDocument as a convenient "anything goes" storage place.

Change-Id: I0ae2f44b89b0db915e78a9b07835000e843d016f
Let's use constant uno name for these.

Change-Id: I5e34f4d7561ef7f4f7b8b3b4d7d06cca072831c7
Finer grained ODS import mode selection.

Change-Id: I18520837f8d25103bf8482a0204b8a7b7740feb1
cp#1000072: Skip styles import for external link cache documents.

This reduces external link update time by 10%.

Change-Id: Ic14d9ea7530818f839330a2004f6aa67ef1e831e
Avoid unnecessary cloning of ScRawToken during token check.

Change-Id: Ia980054437394ef48f7df655411f81d20b9cfa32