Added useful components in extensions package.

[mtabacman]

Moved Pharo extensions to their own package.
Added protocol for events and states setting.
Corrected minor importer issues.

[coveralls]

Coverage increased (+0.5%) to 61.182% when pulling 13b995b on series-protocol into a2590f9 on highchart6-import.

[coveralls]

Coverage increased (+0.5%) to 61.182% when pulling f249491 on series-protocol into a2590f9 on highchart6-import.

[coveralls]

Coverage increased (+0.5%) to 61.182% when pulling ac0cecc on series-protocol into a2590f9 on highchart6-import.

[marianopeck]

Sounds good to me.