Added user choice of name for blocks table export to R workspace

When moving a dataframe of detected / dated bocks to the R workspace
the user now decides what to call that variable that is created in the
workspace - Before, a random number was generated and appended onto a
standard name.
Added the number of SNPs to the blocks table output that HybRIDS generates
Some minor code cleanup - deletion of commented out blocks etc
Started documentation
Finished basic SNP position plotting. TODO:Integrate with HybRIDS engine object and replicate for individual triplets
Finished the basic SNP plotting feature
Fixed a bug which caused an error in cases where a block size was equal to number of SNPs, we now check for this and avoid triggering uniroot if this is the case
Merge branch 'devel'