Add link to code submission guidelines page

Add link to code submission guidelines page on concrete5.org
Fix Link in README

Fix Link in README
Remove on_render_complete from upgrade

Remove on_render_complete from upgrade

Prevent issues with events in upgrades
Add Job Queue Batch Size Constant Defaut to 10

Add Job Queue Batch Size Constant Defaut to 10

- Add JOB_QUEUE_BATCH_SIZE constant
- Set default to 10
t2 can't translate plurals when target language don't have plural form
Remove addHeaderItems for sitemap.js

Remove addHeaderItems for sitemap.js

sitemap.js is now part of ccm.app.js so call returns 404
Merge pull request #1353 from mkly/fix_on_render_complete_install

Remove on_render_complete from upgrade
Merge pull request #1347 from mkly/add_submissions_link_to_readme

Add link to code submission guidelines page
Merge pull request #1354 from mkly/add_job_queue_size_constant_and_change_to_ten

Add Job Queue Batch Size Constant Defaut to 10
Merge pull request #1357 from hissy/zend-translate-plural-bugfix

t2 can't translate plurals when target language don't have plural form
Merge pull request #1359 from mkly/fix_legacy_sitemapjs_add_header_item

Remove addHeaderItems for sitemap.js