Further tidying
Merge pull request #625 from hflynn/rebased/dev_5_0/webplugin_tidy

Tidying webclient plugin page (rebased onto dev_5_0)
merge dev_5_0 -D org -I include -E exclude: PR 619 (Fix hardcoded links to Javadocs in the developer documentation)
merge dev_5_0 -D org -I include -E exclude: PR 620 (Server upgrade bugfix (rebased onto dev_5_0))
merge dev_5_0 -D org -I include -E exclude: PR 621 (Blitz api5 11852 dev 5 0)