More versatile imports

[MeAmAnUsername]

Allow more things with imports. This would increase the ergonomics of the language as it removes some common annoyances

• need to use fully qualified name because module name of multiple qualified modules is the same
• verbosity in function names (spoofax:invokeStrategoStrategy everywhere)
• verbosity in data names (spoofax:IStrategoTerm everywhere)

sub issues

• [x] rename on import: #18
• [x] import functions: #47
• [x] import data: #48
• [x] import multiple at the same time: #49
• [ ] Optional: star import: #50

[MeAmAnUsername]

Use case: #18 and #47 would simplify

func ... = {
  ...
  val cppPerAlgorithm = [compileIrToDistCpp(ir) | ir <- algorithms];
  ...
}

func compileIrToDistCpp(ir: spoofax:IStrategoTerm) -> string = {
  val compiled = oracle:distir:spoofax:task:compileIrToDist(ir);
  val result = oracle:cpp:spoofax:task:prettyPrintAst(compiled);
  result
}

to

import oracle:distir:spoofax:task:compileIrToDist as compileToDist
import oracle:cpp:spoofax:task:prettyPrintAst as printCpp

func ... = {
  ...
  val cppPerAlgorithm = [printCpp(compileToDist(ir)) | ir <- algorithms];
  ...
}