Video channels

There are a few YouTube channels with APL as main subject:
 * DyalogLtd
 * DyalogUsermeeting
 * rikedyp
 * Rodrigo Girão Serrão
 * code_report
 * yernab
 * Jamie Raymond
 * Mi Lia
 * Adám Brudzewsky
 * APLtrainer
 * Aaron Hsu: Co-dfns