[trunk] moved comment marker setup from opj_compress to the library
[trunk] fixes issue #357. MCT is automatically disabled when
subsamppling is detected.
memory cleanup
allocate code block memory in one go, for each tile
added timing code to compress
document
for t1 encoder, use tile data rather than creating a new buffer for each code block and copying into

that buffer
do dc shift in mct for standard lossy and lossless transform
moved max calculation to avoid re-iterating through data
t1 cleanup
separate out init methods for encoding and decoding - get rid of annoying macro
no need to calloc the component data, since it will be over-written with actual data
for single tile encoding, simply re-use image components, rather than

allocating two copies of each component and copying into the tile component
added timing code to decompress
make code block encoding parallizable by creating one t1 struct

per block.
parallelize code block encoding
parallelize decoding