The TEST facility has been removed from the main Facilities.xml file and
into its own test one. The affected unit tests now load the test file if
and restore the original at the end. The FacilityHelper file defines
a simple struct to does this with an object in a scoped manner.

The test file is in the IDFs_for_UnitTesting sub-directory so it does not
get included in the packages.
Refs #7487

This stops it appearing in the list of ISIS instruments in the
first-time setup dialog and elsewhere.

and not as empty strings in file names.

This reverts commit c3722b3c.

It looks like the original commit of this was deleted after it had
already been pushed up, which has made bad things happen.

This reverts commit 4fe9cd9d, and fixes
tests.

This reverts commit a9c8a59a.

Allow filenames specified with the format <<short><operator>>...<short>
where:

<short> = <dir><inst><underscore><runs><ext>
<operator> = "+" or ","
<runs> = lists and/or ranges of (possibly added) runs e.g. "12,13+14,15:20".

See header file of MultipleFileProperty for more info on syntax.

This enables workspaces loaded through the algorithm to have a history that
can be used to reproduce the workspace properly.

MWRunFiles widget of LoadDialog now remembers the exact text a user typed -
in this way any user who types "INST0-50", clicks "Run" and reopens the
dialog is not met by a huge string containing a list of all 51 fully
resolved files, but rather their original input.

Changed the vector<vector<string>> templated versions of the toString and
toValue functions to accept customised delimiters.  This enables us to add
an option for the user to turn off multifile parsing if they are crazy
enough to want to load files with a plus or a comma in their path.

Changed the inner workings of Load for multi files.  No longer calling sub
algorithms with setChild or alwaysStoreInADS.  All workspaces are
essentially created outside the ADS and managed by the algorithm, right up
until the OutputWorkspaces are set.

Tests added where appropriate, but the majority of parsing cases are already
covered by MultiFileNameParser.

Where no instrument is specified in the string to be parsed, the default is
taken from the ConfigService and used instead.

Added a more robust run string parser, with better validation / error
messages.  Will make implementation of multifilename parser simpler, which
is to follow shortly.

This will be used to parse multi filename strings entered by user.
More to follow.  Refs #1419.