added support for jDump from jMDSW

This reverts commit 0be4aa30fe407e81ffd34ddbf1d63fa1a4721711.
Fixes bug 926078 - updates stackwalker

This reverts commit 2d0486fbcf317f3bb90e2828136befa3a95288e0.
enhancements to jDump processing - better sentinel detection

This reverts commit f1d75cee33ec85d1d9433dbb1955428dad9f9ce6.
fixes bug 901177 - no need to rename breakpad to stackwalk anymore

This reverts commit e81493fe2ed4c7807cc621645a46c4d3b40d4ed4.
fixes bug 901177 - build system changes for json stackwalker

This reverts commit 3c1449e32b93f82ff8eebb01b308a6e6181fceb0.
Merge pull request #1593 from rhelmer/bug928145-reland-JSON-stackwalker-changes

Bug928145 reland json stackwalker changes