Add .gitignore file

When you want to see 'git status' including ignored files run:

  git status --ignored
feature #2589: Refactor image create dialog
feature #2589: Refactor template create dialog
feature #2589: Close the image/template creation dialog only if the call succeeds
Feature #2589: libfs.sh "fs_size" handles the new AppMarket size reporting

It now sends a custom header: "OpenNebula-AppMarket-Size" and OpenNebula
obtains the size from that.
feature #2589: Add support for multiple files and templates to the Import dialog of the Marketplace
feature #2589: Show Image and Template ID when a new resource is created
Merge branch 'feature-2589' of git.opennebula.org:one into feature-2589
Feature #2589: Remove '\r' chars from the size
Update comments of kvm.conf file to include RAW behavior
feature #2371: fix bug returning errors from get_hash
feature #2371: do not print extra line in list commands
feature #2371: better fix for the extra new line in list
Merge branch 'gitignore' of https://github.com/cudos/one
Lint help and usage in oned.cc

(cherry picked from commit d9b6cca19589db2b76443edf3bc683c8dac016db)

Conflicts:
	src/nebula/oned.cc
Provide long options for oned

(cherry picked from commit 1f6da357d55d953d2985f6b44a064efe6b7a38fb)
Bug #2689: Adjust to correct MONITORING_INTERVAL variable
feature #2699: convert new lines to spaces in CONTEXT/FILES

(cherry picked from commit ef0b9546192f8bb3e6399924cbc6d0e2a4b2c2b8)
feature #2699: Fix index type in string loop

(cherry picked from commit e6fc3ec37a67ce0af6bc11e23db705c911b4b9d1)
bug #2601: Use ssh_public_key when updating a template