Add deprecation to policy style guide
Merge pull request #339 from nickanderson/style/deprecation

Add deprecation to policy style guide
Remove old screenshots
Update platform support for 3.6
Merge pull request #341 from tzz/doc/containers

Redmine#4096: add docs for data_readstringarray and data_readstringarrayidx and update data container support
Document new option for insert_type in insert_lines.

preserve_all_lines added to core in commit df2c2aee833f41e175605d8c5824d7e7375c0d85
Fix copy/paste errors in header information.
Small editing of language.
Fix linkage to datastate function.

Functions have to come with `()` for linking to work.
document new 3.6 --show-vars and --show-classes in reference
Merge pull request #342 from estenberg/print-vars-classes

document new 3.6 --show-vars and --show-classes in reference
Document where install log is written.
Closes https://cfengine.com/dev/issues/4162
First iteration of 'what's new' page
No shell-session brush
Note "admit" will be deprecated in 3.7
Add documentation for packagesmatching()
Redmine#2038: document string_split() and deprecation of splitstring()
Redmine#4217: clarify readfile() size limit
Merge pull request #340 from nickanderson/cleanup/install.log

Document where install log is written. Closes https://cfengine.com/dev/issues/4162
Redmine#3257: document package listing workaround for Software table