(easy-mmode-defmap): Enable "Up Stack", "Down Stack", and

(easy-mmode-defmap): Enable "Up Stack", "Down Stack", and
"Finish Function" menu map entries for jdb mode.
(gud-jdb-use-classpath): New customization variable.
(gud-jdb-command-name): Add customization.
(gud-jdb-classpath, gud-marker-acc-max-length): New variables.
(gud-jdb-classpath-string): New variable.
(gud-jdb-source-files, gud-jdb-class-source-alist): Add doc strings.
(gud-jdb-build-source-files-list): Likewise.
(gud-jdb-massage-args): Record any command argument classpath
string in `gud-jdb-classpath-string'.
(gud-jdb-lowest-stack-level): New function, finds bottom of current
java call stack in jdb output.
(gud-jdb-find-source-using-classpath, gud-jdb-find-source)
(gud-jdb-parse-classpath-string): New functions.
(gud-jdb-marker-filter): Search/detect classpath information in
jdb's output.  marker regexp updated to match oldjdb and jdb output
formats.  Expand search for source files to include new/old methods
using new functions above.  Do not allow `gud-marker-acc' to grow
without bound.
(jdb): Set classpath information (if available) as jdb is started.
Change `gud-break' and `gud-remove'
to use new %c ("class") escape in format strings.  Add
`gud-finish', `gud-up', `gud-down' command string functions, and
add them to the local menu map.  Update `comint-prompt-regexp' for
jdb and oldjdb.  If attaching to an already running java VM and
configured to use classpath, send command to query for classpath,
else use previous method for finding and parsing java
sources.  Set `gud-jdb-find-source' function accordingly.
(gud-mode): Doc fix.
(gud-format-command): Add support for new %c ("class") escape.
(gud-find-class): New function in support of %c escape.