(bibtex-autokey-expand-string, bibtex-name-part)
(bibtex-entry-type-whitespace, bibtex-entry-type-str)
(bibtex-any-entry-maybe-empty-head, bibtex-string-type)
(bibtex-preamble-prefix, bibtex-string-empty-key): New variables.
(bibtex-entry-type, bibtex-entry-head): Match only valid entries.
(bibtex-entry-postfix, bibtex-known-entry-type-re)
(bibtex-valid-entry-re, bibtex-any-valid-entry-re)
(bibtex-valid-entry-whitespace-re, bibtex-empty-field-re)
(bibtex-field-name-for-parsing, bibtex-remove-delimiters-string)
(bibtex-beginning-of-last-entry): Remove.
(bibtex-parse-field-name): Use bibtex-field-name. Issue error
message if comma is missing but buffer is read-only.
(bibtex-parse-field-text): Handle whitespaces at the end of field
text. Return 3-element list with beginning and end of field text
and end of field.
(bibtex-end-of-text-in-field, bibtex-end-of-field): Change accordingly.
(bibtex-parse-field): Remove arg name. Use bibtex-field-name.
(bibtex-search-forward-field, bibtex-search-backward-field):
Search always delimited by limits of entry. Use more efficient
search algorithms.
(bibtex-name-in-field): Use bibtex-start-of-name-in-field and
bibtex-end-of-name-in-field.
(bibtex-text-in-field-bounds): Handle BibTeX strings when
extracting the content of a field.
(bibtex-text-in-field): Use search limits.
(bibtex-parse-string-prefix): Handle empty string keys based on
bibtex-string-empty-key.
(bibtex-parse-string): Fix docstring.
(bibtex-text-in-string): Use bibtex-text-in-field-bounds.
(bibtex-preamble-prefix, bibtex-strings): New functions.
(bibtex-skip-to-valid-entry): Include preceding whitespace in
BibTeX entries (consistent with other BibTeX functions).
(bibtex-map-entries): Use bibtex-skip-to-valid-entry.
(bibtex-search-entry): Fix docstring. Simplify.
(bibtex-flash-head, bibtex-complete-string-cleanup)
(bibtex-count-entries, bibtex-sort-buffer): Simplify.
(bibtex-beginning-of-first-entry): Use bibtex-skip-to-valid-entry.
(bibtex-parse-entry): New optional arg content.
(bibtex-format-entry, bibtex-autofill-entry, bibtex-url): Use it.
Use bibtex-text-in-field-bounds.
(bibtex-print-help-message): Handle BibTeX strings and preambles.
(bibtex-end-of-entry): Use bibtex-preamble-prefix and
bibtex-parse-string-postfix.
(bibtex-find-text-internal): New function.
(bibtex-remove-delimiters): Use it.
(bibtex-find-text): Use it. New optional arg help.
(bibtex-complete): Handle BibTeX string and preamble entries.
(bibtex-Preamble): Fix order of closing delimiters.
