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:

• Update version numbers where necessary
• Disable mangling of method names to snake_case in API reference generator
• Remove mentions to Python versions older than 3.6
• Update supported Python/platform versions on features.rst
• 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
• Update the collision solids table
• Document InstancedNode
• Document DepthBiasAttrib, mention deprecation of DepthOffsetAttrib
• log_filename_strftime
• Default platform list on Building Binaries page
• Mention texture-reload-num-threads etc. on async load page instead of loader-num-threads
• Merge added navigation in programming #71 (probably restructuring both PandAI and new Recast/Detour under a Pathfinding section)
• Merge Fixed FSM Any state documentation #104
• Update code samples to prefer property interfaces and snake_case
• Update deployment system pages to mention Android
• Document async FSM methods