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
SDT: read each data block into a separate series
SDT: fix block offsets
SDT: one more data block offset fix
Change warning ID from 'bf' to 'BF:lowJavaMemory'

...as suggested by @sbesson.
merge dev_5_0 -D org -I include -E exclude: PR 856 (Initial version of bfCheckJavaMemory)
merge dev_5_0 -D org -I include -E exclude: PR 867 (Ignore text nodes when parsing XMLAnnotation's value (rebased onto dev_5_0))
merge dev_5_0 -D org -I include -E exclude: PR 871 (Fix tiled TIFF reading and writing)
merge dev_5_0 -D org -I include -E exclude: PR 874 (SDT: read each data block into a separate series (rebased onto dev_5_0))