Indicate Flash / RAM usage + Compiler error output

[urish]

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Show how much Flash / RAM is used, e.g.

Sketch uses 2418 bytes (7%) of program storage space. Maximum is 32256 bytes.
Global variables use 192 bytes (9%) of dynamic memory, leaving 1856 bytes for local variables. Maximum is 2048 bytes.

Also show the compiler output (e.g. in case of an error), as requested in #189