feat(app): improve README

build(demo): demo updated to using v1.7

build(plugin): plugin & core version -> 1.7

feat(plugin): plugin now support multi implementation

fix(plugin): avoid duplicate moduleApplication on adding

feat(core): support multi-implementation

feat(demo): more readable error msg for AppJoint Class file not found

build(demo): demo gradle plugin -> 3.4.2, gradle wrapper -> 5.1.1

build(sign): add demo signature for release build

resolve routerInstanceMap hold the object in whole Application running (#27)

build(all): version upgrade to 1.6.1

Merge pull request #20 from LeonDevLifeLog/master

fix(plugin): bug when not set priority on @ModuleSpce

build(all): version upgrade to 1.6

Merge pull request #19 from LeonDevLifeLog/master