Instead of being memoized all at once before display, functions values
are now stored at evaluation time. Fixed some quirks with caching
preparation.
Change-Id: I5d212c271c8c41a6dc9074a15c720f0bccf8ac40
The caches used for function values memoization are now stored in
ContinuousFunctionStore : there are now only a fixed number, instead of
one per function. This effectively enables caching only for the first
few functions on screen, while reducing the memory usage.
Change-Id: I2ade091717f73a14a756fe527c773db8e8627be7
