v0.4.2

• clarify applicability of --no-trunc, only applies to --tree
• fix embedded help information, added note about SELinux
• strip sha256: prefix from view, to match Docker's output style

$ sha1sum dockviz_*                                                                                                                                                                                                                                                                  
350ccbd5e8d40aa1c317de547e714cb79f3fceab  dockviz_darwin_amd64
f35239d91f709ef1e103f6a084c2533a92379117  dockviz_linux_amd64
bb22ebaf81cf161b8d168d3a6203edc7e3f63eeb  dockviz_linux_arm
$ sha256sum dockviz_*                                                                                                                                                                                                                                                                
24b56b817101bc8089be3a46501ae0e5fa0a3a52fa90d640de115295427d49cf  dockviz_darwin_amd64
a8155fd4b2ebd38444c57a0e7af2892a246abec89c9f13b7421721df931b7c3b  dockviz_linux_amd64
67e047770bb4a4a4743a9251c1e0ca4ba7f9086dd7fe3c66670e3ef12ae9fff0  dockviz_linux_arm
$ md5sum dockviz_*
61b51eddb79ea8c5efb12016279b5aa8  dockviz_darwin_amd64
1494ec163dca4b4da7713b93b33b4cc7  dockviz_linux_amd64
ac06344a617196204be619e9fc055d20  dockviz_linux_arm