Provide fuzzier type member matching and more polished sorting.

[olafurpg]

Fixes #620

Previously, the following completion returned empty results

class Foo { def getTimeStamp: Int = 42 }
new Foo().time@@

Now, the completion results include getTimeStamp.

Since we started allowing fuzzier results, we needed better sorting of
completion items in the same category. For example, in the following
example

class Foo {
  def toInt: Int = 42
  def instance: Int = 42
  def intNumber: Int = 42
}
new Foo().int@@

we want the results sorted in the following order

intNumber // because prefix match
toInt     // because literal substring match
instance  // last fallback

This improvement in sorting benefitted non-fuzzy non-type members too.
Previously, the query Iterator returned the order
BufferedIterator,Iterator because they were sorted alphabetically.
Now, the order is Iterator,BufferedIterator instead, a big
quality-of-life improvement.