uwot 0.2.4

Bug fixes and minor improvements

• The installation status of optional dependencies were not being detected correctly. This meant that different packages could be used for initialization in unpredictable ways depending on whether they had been explicitly loaded or not. Thank you hsuknowledge for the report (#134).
• Users of the bbknnR package were suffering from a not-helpful error message when the custom neighbor data contained missing values. An explicit check has been added and although this is still a fatal error, the message should be more informative (#135).
• Fixed a partially-specified parameter name being passed to irlba. Thank you Hugo Gruson for the fix (#136).
• Development-only: fixed an incorrect use of testthat::expect in a unit test. Thank you Hadley Wickham for the fix (#138).