Proper fix for the nlet highlighting. Now allows for loose aiming and always starts the patch cord at the center of the outlet. Inlets from which we currently cannot connect from are grey when highlighted, while ones you can initiate connection from are orange (both colors are themeable inside the css). Also, if trying to connect an impossible connection (signal to non-signal), when hovering over the non-signal inlet during the connection cycle, such an inlet will be also highlighted gray (grey? whatever...). Lastly, updated the highlighting animation--I am really not particularly interested in animation as it tends to slow down the interaction with the patch, so the animation is much shorter and more minimal. Potential value is leaving it as this to provide visibility of the nlet being highlighted when we are already over it with the cursor, which will otherwise occlude the nlet altogether. Another consideration with the currently committed highlight is that it is hollow inside which looks IMO distracting. Curved edges is also distracting since no other aspect of the UI (save for the customized data structures created by the user) is not curved.

* give new cord the same color as selected line (except for vanilla/ext presets)
* make broken object stand out more
* make comment dash sizes match l2ork 1.0
* change xlet hover animation to match new xlet style

fixed segfaults caused by preset_hub_read and preset_hub_readpreset (may want to revisit later to disable the crflag from the binbuf_read_via_canvas and consider implications of potentially running into an A_SEMI which currently does not appear to be likely, or dare I say, possible?)

This is needed to build when some dependencies are installed into
locations outside of /usr.

copied GNU/Linux distro installation instructions from https://github.com/agraef/purr-data/wiki/Installation, and removed references between instructions for different platforms