Loosen peerDependencies versions

[jsebrech]

Describe the bug

Currently peerDependencies lists very specific versions. In projects that include these dependencies but in different versions we get peer dependency warnings whereas actually it works just fine.

"peerDependencies": {
    "@a-ui/core": "~2.3.0",
    "@a-ui/flexboxgrid": "~1.0.0",
    "@angular/animations": "~6.1.0",
    "@angular/common": "~6.1.0",
    "@angular/core": "~6.1.0",
    "@angular/forms": "~6.1.0",
    "@angular/http": "~6.1.0",
    "@angular/language-service": "~6.1.0",
    "@angular/platform-browser": "~6.1.0",
    "@angular/platform-browser-dynamic": "~6.1.0",
    "@angular/router": "~6.1.0",
    "rxjs": "~6.1.0",
    "rxjs-compat": "~6.1.0",
    "typescript": "~2.7.2"
},

Expected behavior

Less restrictive peerDependencies:

• @angular: ^6.0.0 to specify the entire angular 6 line is ok (or if there was some requirement in 6.1, use ^6.1.0)
• rxjs: same
  etc...

[jsebrech]

Also might be a good opportunity to remove rxjs-compat from the peerDependencies list.