Hh megamerge

[hhaensel]

Very many major and minor improvements:

New functionality

• correct evaluation of variables in the declaration part (without brackets)
• automatic type inference also when variables are included
• support of multiple models on one page, even of the same type
• handlers debugger (Stipple.debug())
• mixins support handlers, even with prefix and postfix when defined with @app_mixin instead of @app
• precompilation macro (finally fixed)

Fixes

• correct update of pages when redefining a model
• fixed async calls in onchange functions
• improved reconnection
• improved disconnection warning

Internals

• remove defining eval statements in macros
• removal of model storage and handler storage (better precompilation)
• store handlers with the model instead
• removal of standalone macros @in, @out etc.
• @app and @handlers are now equivalent, @handlers will be deprecated in the future