constructors for abstract matroids
fixed constructor for uniform matroids
- new method for matroids: SomeBasis
- new mutable attributes for matroids: KnownBases and KnownCircuits
- special implication for vector matroids
fixed logical implcation for vector matroids
fixed IsUniform for vector matroids
fixed grave mistake in IsUniform method
methods to compute connected components

Added methods:
- FundamentalCircuitsWithBasis
- IsConnected
- MinorWithLogic
- DirectSumDecomposition

Small fixes:
- changed names of global LI functions
- changed Minor method for abstract matroids
- Circuit method for vector matroids now uses FundamentalCircuitsWithBasis
Tutte computation uses decomposition

- generic TuttePolynomial methods now have requirement IsConnected, new generic method calls DirectSumDecomposition
- DirectSumDecomposition sets IsConnected for its component minors
minor changes to ClosureFunction method for abstract matroids, cleaned up
removed temporary workarounds
beginning documentation, some small fixes along the way
fixed documentation
direct sums

- fixed DirectSumDecomposition
- IndependenceFunction methods for matroids with bases or circuits
- DirectSumOfMatroids method
- \+ and \= operators for matroids
better use of direct sums
- added several fallback methods, e.g. IndependenceFunction, RankOfMatroid and SomeBasis
- dualising now uses DirectSumDecomposition
- changed Display method for abstract matroids
added fallback methods for coloop and loop, fixed logical implication for uniform matroids
added some documentation
some changes for abstract matroids
- changes in documentation
- fixed fallback method for SomeBasis
- changed constructors MatroidByRankFunction and MatroidByIndependenceFunction
some fixes
- fixed SomeBasis (for real this time)
- sensible fallback method for Coloops (without computing duals - this can led to infinite recursion)
- slightly improved IsUniform fallback method
added some fallback methods

DirectSumDecomposition and MinorNL can cause infinite recursion, this is not resolved yet!
fixed infinite recursion in MinorNL