ultimately this is make it more convenient for us to wire up
different elements of the analysis pipeline, without having to
preload everything into memory before we need it
separately the index layer now has a mechanism for storing
internal key/value pairs. this is expected to be used to
store the mapping, and possibly other pieces of data by the
top layer, but not exposed to the user at the top.
defined article word maps for french, italian, irish and catalan
defined elision filters for these same languages
updated analyers for french and italian to use this new filter
irish and catalan still depend on other missing pieces
closes#25
stop words can be loaded from files/bytes, closes#19
stop words loaded for large list of languages, closes#20
defined language specific analyzers for as much as possible right now, closes#21
opened new issues for some of the remaining gaps
removed analyzers (these are now built as needed through config)
removed html chacter filter (now built as needed through config)
added missing license header
changed constructor signature of filters that cannot return errors
filter constructors that can have errors, now have Must variant which panics
change cdl2 tokenizer into filter (should only see lower-case input)
new top level index api, closes#5
refactored index tests to not rely directly on analyzers
moved query objects to top-level
new top level search api, closes#12
top score collector allows skipping results
index mapping supports _all by default, closes#3 and closes#6
index mapping supports disabled sections, closes#7
new http sub package with reusable http.Handler's, closes#22
