Fix problem with directory separator character with commit 5537d701
Implement matrix transpose operator using a single quote character

The character is used as a unary postfix operator with higher priority
than any other operator.

Since the single quote is used for the transpose operator the lexer will
accept literal string only with double quotes. This introduce a major
incompatibility with ordinary Lua syntax.

Conflicts:
	lang/generator.lua
Implement matrix literals

Accept matrix literals in the form [a, b, c; d, e, f] where each
term can be an expression.

The generator rule is implemented using the matrix.build function
that takes a flat table and an integer that indicate the number of
columns.
Implement "use" statement to make module's variables visible as locals

This implementation does not probe the executing Lua state to obtain
a list of the variables in the module. Instead it does probe the Lua
state used by the parser.