#89 Unicode symbols are not supported

[Anonymous]

OpenAxiom does not support unicode symbols like greek letters, math symbols, letterlike symbols, as well as sub- and superscripts.

OpenAxiom should support unicode input, so that the user is able to create alias names.

Examples for possible Aliases:
σ = sigma
ς = varSigma
ρ = ChargeDensity
ℝ = Real;
≤ = '<='
etc.

This basically does not need any changes on how the compiler works, but simply which letters the system accepts.