New Android select example

Fixes #14114
Use bootstrapcdn links
Fixes #14132: add .alert-dismissible to docs examples
Fixes #14133
Fixes #14074: Make open dropdown nav links in navbar use gradients
grunt
Redundant thanks to bb1286a0ab073bce1d18f704d7ac0545ea76c6ef
typos
Fix inaccessible buttons.
Merge pull request #14138 from danielnixon/master

Fix inaccessible buttons.