add first draft of ui meta-model

add gwt module
remove some inject annotations
add sample ui model
add screen sample

fix maven dependencies
add google-gin dependency
Revert "add google-gin dependency"

This reverts commit b80c819eba92c34157e9e7924af9d41b34f3dab3.
add model implementations
package renaming

add fields renderer (not implemented)
renderer implementation using gwt-bootstrap
implementation of ui model with gwt-bootstrap
Constrain the value for non-webkit browsers

Set locale to en
Fix gwt compiler setting
use gwt-bootstrap last stable