Branch off 1.11 manual

[rdb]

Using this issue as a checklist of things to do before/after branching off a 1.11 version of the manual:

After:

• [x] Update version numbers where necessary
• [x] Disable mangling of method names to snake_case in API reference generator
• [x] Remove mentions to Python versions older than 3.6
• [x] Update supported Python/platform versions on features.rst
• [x] Remove notes relating to old macOS pre-10.9 versions
• [ ] Rewrite C++ task and event examples to use lambdas
• [ ] Remove mentions of Cg shaders
• [ ] In fact, overhaul the whole shader section
• [x] Update the collision solids table
• [ ] Document InstancedNode
• [ ] Document DepthBiasAttrib, mention deprecation of DepthOffsetAttrib
• [x] log_filename_strftime
• [x] Default platform list on Building Binaries page
• [x] Mention texture-reload-num-threads etc. on async load page instead of loader-num-threads
• [ ] Merge #71 (probably restructuring both PandAI and new Recast/Detour under a Pathfinding section)
• [ ] Merge #104
• [ ] Update code samples to prefer property interfaces and snake_case
• [x] Update deployment system pages to mention Android
• [ ] Document async FSM methods