add ImportDeclaration constructor
add ImportDeclaration parser
use ModulePath instead of [ProperName]
add Alias constructor to NameKind

This is so that someone smarter/more familiar with the code-base than I
can change the current aliasing behavior so it doesn't have to create
actual `var`s.
add ImportDeclaration type checker
implement declToJs for ImportDeclarations

This changes `declToJs` so it takes an Environment parameter as well.
fix hlint warning in parseImportDeclaration
add passing import test
add failing import example
make Import example more complex
make the ImportDeclaration type checker update the env properly
add import to README
add haskell formatting to import doc
drop potentially confusing lines from doc
simplify ImportDeclaration type checker
fix indentation
Merge pull request #70 from Bogdanp/master

Add basic module imports (#66)