Agenda tweaks

[AmeliaBR]

Based on conflicts / time-zone complaints from presenters, along with some other clean-up.

Re issue #68

Changes made:

• Terence Eden presentation moved from W1D1 to W2D4
• Thijs Brentjens moved from W1D4 to W1D3 (theme merged with internationalization)
• Gethin Rees on vector symbology changed from talk to breakout on W1D3
• Peter R's breakout moved from W1D3 to W1D4
• Accessible Widgets panel & Nicolò Carpignoli's presentation moved from W1D4 to W2D2
• Karel Charvat's presentation & breakout moved from W2D1 to W2D3

Also: Facilitator information added for breakouts

Changes name of commercial stakeholder panel Closes #77