globset: use bstr

This simplifies the various path related functions and pushed more platform
dependent code down into bstr. This likely also makes things a bit more
efficient on Windows, since we now only do a single UTF-8 check for each
file path.

globset/Cargo.toml

@@ -20,10 +20,10 @@ bench = false
 
 [dependencies]
 aho-corasick = "0.7.3"
+bstr = { version = "0.1.2", default-features = false, features = ["std"] }
 fnv = "1.0.6"
 log = "0.4.5"
-memchr = "2.1.0"
-regex = "1.1.0"
+regex = "1.1.5"
 
 [dev-dependencies]
 glob = "0.2.11"