start on new implementation of path expressions
tests for square brackets and helper fns; implement fn getting
add get tests
start implementing expression dependencies rendering
fix dependency getting for square brackets expression
fix dependency getting for fns; add ModelContext
combine expression events and meta
add star at end of dependency paths returned by view functions
Numbers in segments in expression are raw numbers not strings
Changed test to reflect raw numbers in segments
Revert "Numbers in segments in expression are raw numbers not strings"

This reverts commit a1542bc7363267835540c68e6349b3a347ce7e94.
Revert "Changed test to reflect raw numbers in segments"

This reverts commit d1d522a3495aa3d4f18c9f3ab08654515e6f984d.
Convert to using modified esprima to parse template expressions
fixes to expression / context getting interface in coordination with saddle changes
parse literals and unary operators of literals
implement binary and conditional operators of literals
map operators on non-literals to helper functions
Made eachChild contexts contain references instead of numbers
implement array and object literals in expressions
implement derby expression keyword parsing and falsey testing