Improve indent performance

[Deraen]

guns/vim-clojure-static#88

With 6b18b4e test script, master:

FUNCTIONS SORTED ON SELF TIME
count  total (s)   self (s)  function
29646              4.656598  <SNR>35_syn_id_name()
 1532   5.261001   0.407066  <SNR>35_match_pairs()
29028   4.712738   0.186393  <SNR>35_ignored_region()
28332   4.856748   0.155025  <SNR>35_is_paren()
30068              0.059254  <SNR>35_current_char()
  417   5.570994   0.033857  GetClojureIndent()
  417   5.439542   0.032423  <SNR>35_clojure_indent_pos()
  315   1.959061   0.012072  <SNR>35_clojure_is_method_special_case_worker()
  416   0.112460   0.006156  <SNR>35_clojure_check_for_string_worker()
  416   0.116510   0.004050  <SNR>35_check_for_string()
  581              0.003795  <SNR>35_strip_namespace_and_macro_chars()
  130              0.003790  <SNR>35_match_one()
  581              0.003502  <SNR>35_current_word()
  315   1.962500   0.003439  <SNR>35_is_method_special_case()
 1395              0.002532  <SNR>35_bracket_type()
  315              0.001042  <SNR>35_is_reader_conditional_special_case()

Because indent uses the syntax rules, #5 branch already improves this a quite bit:

FUNCTIONS SORTED ON SELF TIME
count  total (s)   self (s)  function
29646              1.478719  <SNR>35_syn_id_name()
 1532   2.199816   0.404030  <SNR>35_match_pairs()
29028   1.617763   0.185423  <SNR>35_ignored_region()
28332   1.798798   0.156209  <SNR>35_is_paren()
30068              0.059659  <SNR>35_current_char()
  417   2.391534   0.034190  GetClojureIndent()
  417   2.312287   0.032532  <SNR>35_clojure_indent_pos()
  315   0.809202   0.011783  <SNR>35_clojure_is_method_special_case_worker()
  416   0.046043   0.006287  <SNR>35_clojure_check_for_string_worker()
  130              0.004105  <SNR>35_match_one()
  581              0.004033  <SNR>35_strip_namespace_and_macro_chars()
  416   0.050047   0.004003  <SNR>35_check_for_string()
  581              0.003524  <SNR>35_current_word()
  315   0.812542   0.003340  <SNR>35_is_method_special_case()
 1395              0.002603  <SNR>35_bracket_type()
  315              0.001093  <SNR>35_is_reader_conditional_special_case()

Testing against Reagent src/reagent/impl/component.cljs.