Page for "tips & tricks"

[ss2165]

Collect common workarounds and tricks to deal with guppy's idiosyncrasies.

Ideas, please comment with more:

• Swap values out of arrays to gain ownership
• with_owned for temporarily taking ownership -> Show with_owned usage in "Ownership and linear types" section #25
• Barriers to force ordering
• Using Stack for recursive use
• Add a section to comptime section showing "python function returning guppy function" trick #35