Initial implementation of NestList.
Initial implementation of FixedPointList.

Also made a tiny adjustment to FixedPoint so that FixedPoint[...] is
exactly the same as Last[FixedPointList[...]], in order to align with
the behavior of Mathematica's FixedPointList, which returns both of the
last two elements even though they are equivalent by the == operator.
Merge branch 'master' of https://github.com/poeschko/Mathics into NestList+FixedPointList
Minor code improvement and documentation edit.
Minor documentation edit.
Merge pull request #112 from freshwater/NestList+FixedPointList

Add NestList and FixedPointList
Merge pull request #104 from sn6uv/Issue100

Bessel Functions and more.
Implement CrossProduct DotProduct and ScalarTripleProduct
add Spherial and Cylindrical coordinates to VectorAnalysis package
add ArcTan[x,y] as atan2 using rules
implement Coordinates, Paramaters, CoordinatRanges and ParamaterRanges
cleanup VectorAnalysis package and add usage strings
Implement Needs
corrections to FindFile
fix bug in Get (acting on Packages)
Get reports first 4 syntax errors only
cleanup code determining whether intepreter waits for another line of input which fixes issues with Get command
fix bug in Get - should evaluate not just parse files
Unprotect symbols in VectorAnalysis package
add VectorAnalysis tests to Needs