Add failed schema accessor (#74)

Add InvalidValue->getFailedSubSchema to receive schema that failed validation, resolves #73

Author: vearutop

Diff for: .travis.yml

@@ -2,6 +2,7 @@ language: php
 php:
   - nightly
   - hhvm
+  - 7.3
   - 7.2
   - 7.1
   - 7.0
@@ -36,5 +37,5 @@ script:
   - if [[ $(phpenv version-name) =~ 7.2 ]] ; then php $HOME/.composer/cache/phpstan.phar analyze -l 7 -c phpstan.neon ./src; fi
 
 after_script:
- - if [[ $(phpenv version-name) =~ 7.2 ]] ; then php $HOME/.composer/cache/ocular.phar code-coverage:upload --format=php-clover clover.xml; fi
- - if [[ $(phpenv version-name) =~ 7.2 ]] ; then $HOME/.composer/cache/cctr after-build --exit-code $TRAVIS_TEST_RESULT; fi
+  - if [[ $(phpenv version-name) =~ 7.2 ]] ; then php $HOME/.composer/cache/ocular.phar code-coverage:upload --format=php-clover clover.xml; fi
+  - if [[ $(phpenv version-name) =~ 7.2 ]] ; then $HOME/.composer/cache/cctr after-build --exit-code $TRAVIS_TEST_RESULT; fi

Diff for: README.md

@@ -123,6 +123,8 @@ For ambiguous schemas defined with `oneOf`/`anyOf` message is indented multi-lin
 Processing path is a combination of schema and data pointers. You can use `InvalidValue->getSchemaPointer()`
 and `InvalidValue->getDataPointer()` to extract schema/data pointer.
 
+You can receive `Schema` instance that failed validation with `InvalidValue->getFailedSubSchema`. 
+
 You can build error tree using `InvalidValue->inspect()`.
 
 ### PHP structured classes with validation

Diff for: composer.json

@@ -6,14 +6,12 @@
     "php": ">=5.4",
     "ext-json": "*",
     "phplang/scope-exit": "^1.0",
-    "swaggest/json-diff": "^3.4.2"
+    "swaggest/json-diff": "^3.5.1"
   },
   "require-dev": {
     "phpunit/phpunit": "4.8.35",
-    "swaggest/code-builder": "dev-master#e0c5c0612fd241d2d120e5ddef91cda9edc208ee",
-    "swaggest/php-code-builder": "dev-master#3e643924445eb0f8d13dd011a57a42ce75629892",
     "phpunit/php-code-coverage": "2.2.4",
-    "codeclimate/php-test-reporter": "^0.4.0"
+    "codeclimate/php-test-reporter": "0.4.0"
   },
   "license": "MIT",
   "authors": [
@@ -36,9 +34,6 @@
       "Swaggest\\JsonSchema\\Tests\\": "tests/src/"
     }
   },
-  "scripts": {
-    "gen-json-struct": "php ./tools/generate_json_structures.php"
-  },
   "config": {
     "platform": {
       "php": "5.4.45"