add openLookup api method

[balmas]

dependent on alpheios-project/components#607 and alpheios-project/components#608

add an api method to the embedded library which can be called by a client-defined handler to open the lookup component.

[balmas]

@kirlat this (together with related issues in components and alpheios_nemo_ui) is next priority after alpheios-project/node-build#16

[kirlat]

Merged into master