Merge file annotation writing examples into annotation section

- Improve readability of the annotation writing subsection
- Merge Updating file annotation into Writing annotations
Improve description of getImages() by container signature
Homogeneize comments across the MATLAB documentation page
Minor fixes
Remove thumbnail methods from the MATLAB documentation page
Additional fixes suggested by @jburel
merge dev_4_4 -D org -I include -E exclude: PR 571 (Document latest OMERO.matlab functions (rebased onto dev_4_4))