Use I shapelet for undefined other shapelets

Bug 1491: Fix of somewhat confusing side effect of the dilation operation when the Equal polarisation setting was removed. Reported by A. Biggs.

Bug 1491: Fix of bug reported by A. Biggs: it was not possible to write individual polarizations to a set -- the tools would always write the first mask (XX normally) to the set. Default strategy was not affected.

Bug 1681: Print which configuration files are being read. This cannot be done using the logger, because it is not yet configured at that moment.

Made it possible to use an expression in nchan for startchan and nchan

bug 1362: now conforms to required style (still 13 pages though and references are not self-contained)

Bug 1607: Automatic checkin of merge of branch MAC-20101206-1_0-release-branch (svn-17729 - svn-17762) in trunk

bug 1362: print written/dropped stats at end of obs in Storage, and reduced block reading message to DE
BUG level

First version