edit default errors

[nbriz]

migrating this issue over from: netizenorg/netnet.studio#40
(remember to close that once this is closed)

need to think through the default set of html/css/js errors a bit more, now that we've had some time to write code in netnet, there are a few errors that feel more annyoing then they are helpful, just a couple examples:

• attributes like controls="true" && checked="true" are often just written controls && checked... but netnet get's picky about this

• the JS "defined but never used" also feels more annoying then it is helpful b/c it fires essentially everytime u create any variable, && continues to fire until the variable is used. my standardJS plugin in Atom does this too... but for some reason it feels more aggressive in netnet... or is this just me?

• the JS "you're trying to sue the variable ____, but you haven't previously created/defined" can be misleading when using libraries that introduce new vars into the global scope

maybe we could also consider adding more control over errors in the Functions Menu, something that allows u to toggle through different error levels (warnings vs errors for example) or maybe toggle them all off all together?

maybe we also need to add another higher-level error logic that considers the entire array of errors present && deduces certain issues from the particular set (for example the issue that happens when someone hasn't closed a tag && netnet thinks they're trying to us the < char, rather than understanding the a char is missing