Unarchive zip file after fetcher downloads the package (#301)

Fetcher now uncompresses archive files. 

This is triggered by automatically detecting the file format, although maybe we should make that explicit or at least move the detection into the client.

glide.lock

@@ -1,5 +1,5 @@
-hash: 51b5eda27974aac228f42002cb0a9f89bf2f79d36a574a3694c142c2f83e4042
-updated: 2017-03-24T11:01:00.667996869+08:00
+hash: 2703407b4ae6e28cd146b14ff6b77175a17f0f944f7d75131ac0fa0406793d5b
+updated: 2017-08-27T22:38:51.57334855+08:00
 imports:
 - name: github.com/blang/semver
   version: 60ec3488bfea7cca02b021d106d9911120d25fe9
@@ -37,6 +37,14 @@ imports:
   - reference
 - name: github.com/docopt/docopt-go
   version: 784ddc588536785e7299f7272f39101f7faccc3f
+- name: github.com/dsnet/compress
+  version: 0ae8e136a5df9e3caf6c0f69983608b07438411b
+  subpackages:
+  - bzip2
+  - bzip2/internal/sais
+  - internal
+  - internal/errors
+  - internal/prefix
 - name: github.com/emicklei/go-restful
   version: 3d66f886316ac990eb502aaa89ea38546420b8b7
   subpackages:
@@ -64,6 +72,8 @@ imports:
   subpackages:
   - jsonpb
   - proto
+- name: github.com/golang/snappy
+  version: 553a641470496b2327abcac10b36396bd98e45c9
 - name: github.com/google/gofuzz
   version: fd52762d25a41827db7ef64c43756fd4b9f7e382
 - name: github.com/gorilla/context
@@ -72,6 +82,10 @@ imports:
   version: 3a5767ca75ece5f7f1440b1d16975247f8d8b221
 - name: github.com/gorilla/mux
   version: 392c28fe23e1c45ddba891b0320b3b5df220beea
+- name: github.com/howeyc/gopass
+  version: bf9dde6d0d2c004a008c27aaee91170c786f6db8
+- name: github.com/imdario/mergo
+  version: e3000cb3d28c72b837601cac94debd91032d19fe
 - name: github.com/influxdata/influxdb
   version: b7bb7e8359642b6e071735b50ae41f5eb343fd42
   subpackages:
@@ -92,6 +106,8 @@ imports:
   - buffer
   - jlexer
   - jwriter
+- name: github.com/mholt/archiver
+  version: fe92d3d85a514d2752ad3b61ec412b598a2754f9
 - name: github.com/nats-io/go-nats
   version: 6949c8e06a246e4177961aab22940b5c411e48f0
   subpackages:
@@ -107,8 +123,16 @@ imports:
   - util
 - name: github.com/nats-io/nuid
   version: 289cccf02c178dc782430d534e3c1f5b72af807f
+- name: github.com/nwaples/rardecode
+  version: f22b7ef81a0afac9ce1447d37e5ab8e99fbd2f73
 - name: github.com/pborman/uuid
   version: 3d4f2ba23642d3cfd06bd4b54cf03d99d95c0f1b
+- name: github.com/pierrec/lz4
+  version: 5a3d2245f97fc249850e7802e3c01fad02a1c316
+- name: github.com/pierrec/xxHash
+  version: a0006b13c722f7f12368c00a3d3c2ae8a999a0c6
+  subpackages:
+  - xxHash32
 - name: github.com/PuerkitoBio/purell
   version: 8a290539e2e8629dbc4e6bad948158f790ec31f4
 - name: github.com/PuerkitoBio/urlesc
@@ -125,8 +149,18 @@ imports:
   version: f1f1a805ed361a0e078bb537e4ea78cd37dcf065
   subpackages:
   - codec
+- name: github.com/ulikunitz/xz
+  version: 0c6b41e72360850ca4f98dc341fd999726ea007f
+  subpackages:
+  - internal/hash
+  - internal/xlog
+  - lzma
 - name: github.com/urfave/cli
   version: 0bdeddeeb0f650497d603c4ad7b20cfe685682f6
+- name: golang.org/x/crypto
+  version: 9477e0b78b9ac3d0b03822fd95422e2fe07627cd
+  subpackages:
+  - ssh/terminal
 - name: golang.org/x/net
   version: 6acef71eb69611914f7a30939ea9f6e194c78172
   subpackages: