Merge pull request #220 from uronce-cc/master

add information to 'In Memory Files' page
format
fix UI: host/browse or host/browse? or host/browse?(anything except 'path') will crash due to NullPointerException
fix UI: set invalid offset in display file will crash, offset should be numbers and should be in range [0, size(file)]
fix UI: display file may crash due to IOException