v0.2.2

GTPSA v0.2.2

Diff since v0.2.1

Fixed type promotion
Added function "one"
Changing descriptors requires number of variables/parameters to agree
erf and erfc imported from SpecialFunctions now
"show" works with Vectors containing TPSs that have different Descriptors (a warning is issued)
cutord bug fixed when order=0 (heap corruption, fixed in jll)
Tracking example expanded
Docs update and cleanup

Merged pull requests:

• v0.2.2 (#92) (@mattsignorelli)
• Update Project.toml (#94) (@mattsignorelli)