v0.2 - New SNP methods

• Removed kSNP3 as it was creating too much conflicts for the conda environment creation. Please use v0.1 if you want to be able to produce a pan-SNP tree. Consequently, only core-SNP methods remain.
• Addition of snippy v4.6.0 as alternative method to find SNPs. Now default method. Use FastTree to make tree.
• Addition of phame v1.0.3 as alternative method to find SNPs. Seems to have lower resolution than snippy. Use FastTree to make tree.
• README.md updated accordingly.