Update POMs to point to mirror of the cppwrap plugin

This removes the dependency on maven.imagej.net, which has been causing
problems for Travis and Jenkins.
Initial version of bfCheckJavaMemory

This displays a warning message if the heap space is below 512m.  Only
functions that call setId currently call bfCheckJavaMemory.
Update copyright year
Allow the minimum memory value to be specified

The default value is still 512m.
bfCheckJavaMemory: fix typo in function definition
bfCheckJavaMemory: use 'warning' instead of 'fprintf' for logging
Change warning ID from 'bf' to 'BF:lowJavaMemory'

...as suggested by @sbesson.
Add unit test class for bfCheckJavaMemmory() function
Combine warning messages to have one warning with specified ID
Ask Travis to test the top-level Ant compile targets
Fix dependencies for the compile-ome-io target
Add -x option to shell script
Fix ant build target to prevent infinite loops
Merge pull request #896 from melissalinkert/rebased/develop/matlab-memory

Initial version of bfCheckJavaMemory (rebased onto develop)
Merge pull request #899 from joshmoore/rebased/develop/compile-targets

Test compile targets with Travis (rebased onto develop)
Merge pull request #866 from melissalinkert/rebased/develop/cppwrap-mirror

Update POMs to point to mirror of the cppwrap plugin (rebased onto develop)