Major styling/layouts update, better for mobile

• Update package lock 54f7897
• Improv/styling rework (#74) 7934b6c
• examples/mux-video: Add mux-video example. (#84) d4a8e37
• fix/react-rte: do proper existence checking in media element in case it hasn't been slotted yet. (#81) c442a39
• Chore/testing infrastructure (#78) cb55c32
• Feat/cc button simple (#76) 09341ab
• Change "standard" example to "advanced" (#77) 49f7600
• Introduced a theme element (#42) f6132b6
• Improv/rearch simplify expand mue association v2 (#62) dea9a68
• Open /examples page on yarn dev (#70) 2d1c636
• fix/range-background: Make sure numeric values are removed as attributes if/when NaN (instead of set). (#65) 701e876
• Fix playback rate API bug/typo (#63) 2f65066
• Improv/a11y phase 1 (#58) ec4f0e3
• Merge pull request #51 from cjpillsbury/bugfix/media-control-bar-outside 3ab43d0
• bugfix/media-control-bar-outside: juggle names so 'most likely used media-controller methods' are the ones named associateElement/unassociateElement. 9337e6d
• bugfix/media-control-bar-outside: remove no longer used elementUtils module. c11a5d6
• bugfix: migrate components to support outside assoc w/media-controller (thumbnail preview). 3bd141f
• bugfix: migrate components to support outside assoc w/media-controller (displays). db50c05
• bugfix: migrate components to support outside assoc w/media-controller (ranges). ff017f4
• bugfix: migrate components to support outside assoc w/media-controller (buttons). 52701a2
• bugfix/media-control-bar-outside: re-add support for media-control-bar that is not a descendant of media-controller. Use element id for consistency with HTML norms. Support runtime association/disassociation. e8132db
• Improv/a11y plus styling buttons (#48) 3ff5fb0
• Update architecture notes (#54) 546c121
• improv/a11y-plus-styling-container: directly apply aria roles and labels to container/controller custom element to make custom styling easier. (#49) d5e5c79
• Improv/rearch simple components (#44) 7e48adc
• Improv/dev env snowpack (#45) 6b916db
• Fixing a codepen example alignment issue dde90be

v0.2.2...v0.4.0