Warn on GraphQL parser exceptions

[hekard2l]

When GraphQL parse fails to parse file(s) errors are silently ignored.

Was having an issue with a whitespace character in one of our .graphql files which was rather difficult to trace. This character is added as a result of saving the file in XCode, so it'd be a common use case.

Example:

Warning: error parsing GraphQL file "Queries/Enrollments.graphql"
Syntax Error: Cannot contain the invalid character "\u0010".

Queries/Enrollments.graphql (6:1)
5: }
6: 
^
7: 

at syntaxError (/../code/apollo-cli/node_modules/graphql/error/syntaxError.js:24:10)
at readToken (/../code/apollo-cli/node_modules/graphql/language/lexer.js:174:34)
at Object.lookahead (/../code/apollo-cli/node_modules/graphql/language/lexer.js:61:43)
at Object.advanceLexer [as advance] (/../code/apollo-cli/node_modules/graphql/language/lexer.js:52:33)
at skip (/../code/apollo-cli/node_modules/graphql/language/parser.js:1284:11)
at many (/../code/apollo-cli/node_modules/graphql/language/parser.js:1349:11)
at parseSelectionSet (/../code/apollo-cli/node_modules/graphql/language/parser.js:272:17)
at parseOperationDefinition (/../code/apollo-cli/node_modules/graphql/language/parser.js:209:19)
at parseExecutableDefinition (/../code/apollo-cli/node_modules/graphql/language/parser.js:166:16)
at parseDefinition (/../code/apollo-cli/node_modules/graphql/language/parser.js:132:16)

The stacktrace isn't useful, but e.message does not contain the filename, line number and preview.

[apollo-cla]

@hekard2l: Thank you for submitting a pull request! Before we can merge it, you'll need to sign the Meteor Contributor Agreement here: https://contribute.meteor.com/

[jbaxleyiii]

@hekard2l this is awesome! Thank you so much!